Road-mobiles, as the name indicates, are
long-distance nuclear missiles mounted on huge trucks. The advantage to these roving city-killers is that they’re hard to find, and make first-strike planning pretty tough. Fixed-place ICBMs, buried in silos, never move. Since they’re the equivalent of potted plants (or sitting ducks?) you can plan strikes against them weeks, months, even years in advance, which increases their vulnerability. Road-mRoad-mobiles also make sense for a large land power like Russia, which has most of its missiles inside its borders. The United States, unsurprisingly for a maritime power, has most of its megatonnage roaming around under the world’s oceans. (The entire UK deterrent is completely submarine-based.) While it’s a little harder to drive missiles around on land — where satellites can see them, and where, you know, people
live — it’s the best approximation to the sea-based deterrent.Road-mobiles, by contrast, might never be in the same place they were the week before. (Think of them as land-based submarines.)...
There are a few reasons that mobile missiles make sense. First, countries with a small strategic deterrent with very few ICBMs, like China or a new power just getting into the game —
yes, I mean North Korea — will want to have every edge in protecting its deterrent from a surprise attack. Not surprisingly, the idea of digging a hole and putting a missile in it, where the enemy can take pictures of it all day and program its position to the centimeter into its own attack force (or into a missile defense grid, if one is ever built) isn’t very appealing.
Road-mobiles also make sense for a large land power like Russia, which has most of its missiles inside its borders. The United States, unsurprisingly for a maritime power, has most of its megatonnage roaming around under the world’s oceans. (The entire UK deterrent is completely submarine-based.) While it’s a little harder to drive missiles around on land — where satellites can see them, and where, you know, people
live — it’s the best approximation to the sea-based deterrent.
http://tomnichols.net/blog/2012/11/14/russia-road-mobile-icbms/
They present an advantage when mobile..